1. Field of the Invention
This invention relates to tape carriers for electronic and electrical devices, including semiconductor chips.
2. Introduction to the Invention
When electronic and electrical devices are to be supplied to a desired location, it is conventional to make use of a tape carrier comprising spaced-apart pockets, with one device in each pocket. Such pocketed tapes are sometimes referred to as "embossed" tapes. The tape carrier often has sprocket holes on one or both edge portions so that it can be handled in a controlled manner. Ordinarily, the pockets are formed in the tape, and a cover tape, and/or a mechanical retaining member in the pocket, and/or a pressure sensitive adhesive (PSA) at the bottom of the pocket, are used to retain the electronic device in the pocket until it is removed, e.g. by means of a vacuum tool. In some cases, the pocket has a hole in the bottom so that an ejector pin can be pushed through the hole to eject the device. These known carrier tapes have one or more of a number of disadvantages. For example, different carriers are usually needed for different devices, since the pockets and the mechanical retaining members must be customized to particular devices, to ensure that the device does not fall out of the pocket and remains in a desired location and orientation in the pocket. Use of PSAs can suffer from the disadvantage that some of the adhesive may stick to the device, after it has been removed from the carrier; another disadvantage is that the level of adhesion can change with time and/or ambient conditions, with removal of the device generally becoming more difficult with time. Use of an ejector pin can damage the device if the contact force is excessive. In a variation of the "pocketed tape", apertures are punched in a tape and the apertures are converted into pockets by means of a strip of a PSA tape longitudinally bonded to the bottom of the punched tape or two strips of PSA tape with a small gap between them through which an ejector pin can be pushed. Tapes of this kind suffer from the disadvantage that the PSA tape does not afford good mechanical protection to the device, and the other disadvantages of the PSAs referred to above.
Copending, commonly assigned U.S. patent application Ser. No. 08/680,390, filed Jul. 15, 1996, by Victor Althouse and Christopher Brodie, discloses an improved pocketed tape carrier which includes, in each of the pockets, a fastening member comprising a flexible polymeric film which is selectively secured to the floor of the pocket so that the fastening member comprises
(a) a fixed portion which is attached to the floor of the pocket, and PA1 (b) a release portion which is composed of a flexible polymeric film and which can be deformed away from the floor without detaching the fixed portion from the floor. PA1 (1) a flexible support film which PA1 (2) within each of the pockets, and covering at least part of the central portion thereof, a fastening layer of a material to which the electronic or electrical device will releasably adhere. PA1 (1) a flexible support film which PA1 (2) within each of the pockets, a fastening member having one of said devices releasably attached thereto. PA1 (1) providing a tape member which comprises a flexible support film which PA1 (2) subjecting the floor of each pocket to a treatment which reduces the resistance of the floor to deformation into the pocket; and PA1 (3) placing a fastening layer of a polymeric material on the floor of each pocket. PA1 (A) providing an assembly of electronic or electrical devices according to the second aspect of the invention; PA1 (B) advancing said assembly through a work station; PA1 (C) sequentially subjecting the central portion of the floor of each pocket to a treatment which deforms a central portion of the pocket, thus weakening the attachment between the fastening member and the device; and PA1 (D) sequentially removing each device from each pocket while the central portion of the floor of the pocket is deformed.
Copending, commonly assigned U.S. patent application Ser. No. 08/616,675 now Pat. No. 5,682,731 filed Mar. 15, 1996, by Victor Althouse, describes a pocket-free carrier tape for electronic and electrical devices which comprises a carrier member which comprises a pocketless support film and a fastening layer on the support film, and a deformable cover film which is separably attached to the fastening layer.